Shearing devices, particularly typified by manually operated hedge clippers and lopping shears are often used to cut shrubbery beyond the normal arm reach of the operator. To extend the reach requires telescopic or extendable handles. Such handles are of necessity light to enable the operator to effectively cope with the added distance. Extending of the handles, however, increases the distance from the handle grip to the axis or pivot point of the shears, providing the operator with a tremendous mechanical advantage which can generate considerable torque about the pivot axis of the shearing device. As a result, attempts to cut large or cut resistant objects with such devices can result in damage to the device, generally to the light weight, extendable handles. Bending and distortion thereof often occurs.
Clutch mechanisms to cause slippage when undesirable overload occurs in a mechanical device are, in general, well known. Such prior art clutch mechanisms, however, tend to be complex, and generally too heavy and bulky for effective use in hedge clippers.